The US is holding two female weapons scientists, Rihab Rashid Taha and Huda Salih Mahdi Ammash, but says it has no plans to release them.
The UK says it has no Iraqi women in its custody.

Mr Straw said the British government was doing everything to secure Mr Bigley's release but could not give in to terrorists.

He added that it would be idle to pretend that there was a great deal of hope.

Reacting to the video, he told the BBC: "It's adding torture to the appalling situation which these evil terrorists have placed Mr Bigley in. Of course our hearts go out yet more to him and his family.

"[But] I'm afraid to say it cannot alter the position of the British government."

After Mr Bigley's appeal, his son Craig, 33, issued in a statement to the kidnappers on behalf of the family: "Be merciful, as we know you can be. Release Ken back to his wife and family."

Mixed messages

Mr Bigley, 62, was among three Western civilian contractors kidnapped a week ago in Baghdad.

Video footage released on Monday showed American Eugene Armstrong being killed by a masked man thought to be al-Zarqawi.